The DOM Level 2 spec has this to say about Node.ownerDocument:
> The Document object associated with this node. This is also the Document
> object used to create new nodes. When this node is a Document or a
> DocumentType which is not used with any Document yet, this is null.
This specifies a couple of cases when ownerDocument is null, but it is
not clear if these are the only times that it is null. For example,
when I create a new Element or other node with one of the
Document.createXXX() methods is the resulting node required to have its
ownerDocument property set?
David Flanagan